Title

Observation of a New Excited Beauty Strange Baryon Decaying to Ξb- π+π-

Document Type

Article

Abstract

The Ξb-π+π- invariant mass spectrum is investigated with an event sample of proton-proton collisions at s=13 TeV, collected by the CMS experiment at the LHC in 2016-2018 and corresponding to an integrated luminosity of 140 fb-1. The ground state Ξb- is reconstructed via its decays to J/ψΞ- and J/ψΛK-. A narrow resonance, labeled Ξb(6100)-, is observed at a Ξb-π+π- invariant mass of 6100.3±0.2(stat)±0.1(syst)±0.6(Ξb-) MeV, where the last uncertainty reflects the precision of the Ξb- baryon mass. The upper limit on the Ξb(6100)- natural width is determined to be 1.9 MeV at 95% confidence level. The low Ξb(6100)- signal yield observed in data does not allow a measurement of the quantum numbers of the new state. However, following analogies with the established excited Ξc baryon states, the new Ξb(6100)- resonance and its decay sequence are consistent with the orbitally excited Ξb- baryon, with spin and parity quantum numbers JP=3/2-.

Department(s)

Physics and Engineering

Publication Title

Physical Review Letters

Volume

126

Issue

25

Publication Date

6-25-2021

DOI

10.1103/PhysRevLett.126.252003

ISSN

00319007

E-ISSN

10797114

Comments

The CMS Collaboration includes over 100 authors. This record includes the Bethel author and the first 5 authors listed. The full list of authors can be viewed on the downloaded document or at the original publisher's website - https://doi.org/10.1103/PhysRevLett.126.252003

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